add support for component.io. 

Leaflet/Leaflet dep is missing (see below) as Leaflet's repo has not yet promoted component changes?
 
https://github.com/Leaflet/Leaflet/commit/ce4b77fe811f6ade59eabfdebaf4991c3938cf59

You will need to manually add this bit once that is done:

```json
"dependencies": {
    "leaflet/leaflet": "0.6.x"
  },
```